The pickup is one of the most important chain in a analogue set-up since it is the device that actually converts information contained in the grooves of a record to an electric signal(it is in other words a transducer). Most high quality types are Moving Coil (MC) where the coil assembly is fixed on the end of the cantilever thereby making the user replacement of the stylus near impossible, most budget types however are Moving Magnet (MM) whereby the coils are fixed in the cartridge body but the magnet is on the cantilever, this simplifies the stylus/cantilever assembly greatly and means that in almost all cases the stylus is user replaceable. Other variants like Piezoelectric or Moving Iron (MI) are also to be found, although rare in new equipment.
The Moving Coil type is by far the most common type of a high quality pickup, the mechanical energy is converted into electrical energy by using a wound copper coil which is fastened to the end of the cantilever, on the opposite end to the stylus, while a magnet is fastened into the housing or frame of the pickup itself. This system has a number of advantages, it has a low moving mass, has a high structural integrity since the unit is usually a whole with the stylus/cantilever not being user replaceable. There were some MC designs made in Japan in the late 70's and early 80's that had user replaceable stylus assemblies but they are rare enough these days to be immaterial. There are plenty of specialised concerns making and servicing them meaning that there is a bewildering array of specialist variants and services available for MC designs. The disadvantages are they are more expensive to make since it's much more difficult to construct the coil piece on the end of the cantilever that it is to build it into the pickup housing, for the same reason it's more complicated to automate the manufacture of them and thus there are few worth while low end designs, the very best MC pickup usually have a low or very low output since they have fewer windings on the coil to minimise the mass on the cantilever, but this puts strains on the amplification requiring much more gain than what you can expect with a similar MM design, amplifying those signals has become something of a black art and the how's and the whatnots are endlessly debated on, the lack of user replaceable stylii means that they have to be sent to the manufacturer or a specialised service company when it gets worn out and so on. There are variants on the theme, silver is occasionally used in the coil windings to gain more efficiency, and in Asia gold is also popular but in general that is frowned upon in the West although the softer gold wire actually makes for more precise winding and gold is chemically more stable, platinium is also an exellent choise to coil winding, possibly the best material availabe but very difficult to source and either material is typically only on expensive variants, better coil winding robots have meant reasonably priced high output designs are slowly becoming more commonplace. The moving coil pickup was developed by the Danish company Fonofilm Industri (now Ortofon) in the late thirties/early 40's as a cutterhead which was turned into a commercial pickup in 1948 (which is still available BTW as the Ortofon Mono 63) with a stereo variant appearing in the 50's as the SPU, all current true MC designs are direct or indirect descendants of those pickups. The large support industry for MC designs has meant that old designs can be kept going almost endlessly, cantilevers and stylii can be replaced and coils repaired although there are a few exceptions where something specialised like a ruby cantelever has to be replaced with a more generic part.
The Moving Magnet can be seen as the inverse of a MC with the magnet being mounted on the end of the cantilever while the coil is fixed into the pickup housing. This is the most common type of pickup made today and has a number of advantages such as it's much simpler to mass manufacture than an MC, is very linear, since the cantilever construction is very simple the use of a replaceable stylus is made possible, it's very effective (Sensitive) compared to a MC and most amplifiers come with inputs intended for use directly with an MM pickup. The disadvantages are that it's slightly less accurate than an MC due to a higher moving mass, the (almost universal) use of a replaceable stylus means that the pickup housing is less rigid, it's has a tendency to distort on records that have high modulation levels such as 45's and 12's dance records, the high end response has a tendency to be slightly damped and the general perception that they are inferior to MC's means that there are very few specialised concerns making high end models these day's meaning that it's almost impossible to find a MM with a modern line contact stylus and better cantilever materials which means that in practice, as opposed to theory, they do not track as well as high end MC designs and finally there are very few if any persons out there there that specialise in repairing them, making older models more vulnerable to the ravages of age. The MM has been with us since the 1910's at the least although in the form that we know it today it's based on a design that was patented by ELAC in 1957 (the later USA patent was issued to Shure Inc. but is just a copy of the ELAC one). Note that in old ads for pickups MM carts are sometimes called "Induced Magnet", "Moving Armature", "Induced Flux" or "Variable Reluctance", not all of those descriptions are technically correct BTW.
The Ribbon pickup was popular in the 50's as a high end device, technically it's best described as a 2D variant of the moving coil principle although the basic idea behind it is similar to a variant of the ribbon loudspeaker principle, but the coil is wound onto a sort on an U frame connected to the cantilever with a magnet fastened to the pickup housing, this type of design was mostly seen in the UK, since the ribbon pickup is only useable for Mono pickups it disappeared in the stereo age.
The Moving Iron is basically a moving coil pickup with iron in the coil, this makes it more effective as a generator (ie you get a higher output voltage) but they do not appear to sound as good as similar MC designs. There are quite a few variants of the principle, some of them designed more like a MM pickup with the coil partially in the housing, the main problem with any sort of MI design is the presence of iron, the pole pieces end up rusting and even falling off, the actual lifetime differs from manufacturer to manufacturer. The best known MI basic design is the one that Grado patented in 1957 or thereabouts but most modern devices owe nothing to that patent except in name.
The Piezoelectric pickup takes advantage of the fact that certain crystal structures generate electricity when put under mechanical stress, this system is remarkably efficient, in fact so much so that a crystal pickup can generate enough voltage to drive a line input directly and is very cheap to manufacture but has problems with linearity, the RIAA pre compensation Eq. is designed to accommodate the characteristics of this sort of transducer. Almost all early piezoelectric pickups were made out of crystals grown in Rochelle Salts solution and were almost all budget devices although in the 50's and early 60's there were a few designs that attempted to gain higher quality, in some cases there was a noticeable improvement in linearity but that created a problem with the pre compensation and in those cases you will often find resistor networks inside the pickup that modify the signal back to that of a normal crystal pickup. As for old crystal pickups, these can be repaired or rebuilt but the crystal element deteriorates over time so even if you find a NOS unit chances are that you cannot use it without a rebuild or that the performance will be abysmal, thankfully however most carts of this type are still being made (or equivalents). In the 60's ceramic pickups started to replace the crystal pickups in the marketplace, they have the exact same characteristics as the ones made out of Rocelle salts but are easier to assemble and last much longer, longer than either MM or MC's in fact and in the 70's ceramic designs appeared that competed with other high end pickups in quality. Piezoelectric pickups are sometimes seen referred to as "Electrets" and the first company to design crystal pickups was Brush Development Company in the 1910's although they never actually made them themselves commercially but rather licensed the concept and the first models appear to have turned up for sale in the 1930's.
The Optical pickup pops up from time to time, it's basically a photocell that senses the movement of the cantilever and thus acts as a transducer, in theory should sound great and have a long livetime but in practice neither objective was really archived. First seen commercially in the early 40's on Philco equipment but the best models were made by Yamaha Corp. in the 70's and cost as much as a high end MC pickup.
The Electrostatic pickup is yet another obscure device from the 50's that died out with the mono age since it is difficult to fabricate in 3D, they did not require an energiser (i.e. they were self energising like a Koss Electrostatic headphone)
The Digital Pickups are almost unheard of as commercial devices (one made today at a price of around 15k €) but do crop up from time to time, in them the movement of the cantilever is digitised directly in the pickup and transferred to an audio system as digital data. The reason that they are not more commonplace is the price and the need for computing power, the overhead of just the RIAA pre compensation calculation does reqire at the least a 40 bit headroom to sound reasonable and preferably 56 bits or higher with a 16 bit 44KHz signal but that means that it will probably not work in real time on a 32 bit computer (i.e. a common PC) unless there is a trade-off somewhere and with a higher sampling or bitrate the problems mount, and that is without counting in all the other calculations needed, all of this computing can be accomplished in the analogue world with a 20p op-amp (most people think Eq. is cheap and easy to do digitally but that depends on what sort of Eq. that is and to what spec.).
The way a pickup is mounted into a tonearm may seem like a given thing or an irrelevant subject, however the mounting system may influence how a well a record player functions since it governs how well the pickup and the arm mate together, both in a straight mechanical sense in how well the stylus is aligned to the groove and as is how tight the 2 mate but that affect the self-resonance of the arm and hence the sound quality. By far the most common arrangement of fastening the pickup to the tonearm of a home audio system is the 1/2 inch mount and the most common type in broadcast or DJ systems is the Ortofon mount.
Standard/Half Inch Mount
The main disadvantage of the elliptical shape is simply the extra cost of hand polishing it and this kept it confined to the more expencive pickups and the aftermarket until the 1970's, when a certain European manufacturer of spherically polished industrial quality diamonds intended for use in watch movements designed a revolutionary new automatic polishing machine that was meant to make sperical shaped diamonds but due to design fault spat out elliptical ones at an alarming rate. After it was pointed out to the gent who owned the machine that this could be a selling point rather than a disaster we started to see mid priced pickups featuing this stylus shape and by the time the 90's were upon us some budget models started to feature them. Today there is no real price difference between the raw price for an industrial quality elliptical and shperical stylus, the only thing is that it is slightly more diffucult to mount an elliptical by hand than a sperical due to the alignment needed, but even that has been overcome and Ortofon uses elliptical stylii in all of their budget bodel including the cheapest ((OEM)) models..
A Killick stylus profile
The stylus lifetime
The theory of RIAA EQ
Tweaking your record player
Understanding The Issues Behind Cartridge Alignment
Why Ortofon and Why moving Coil ?
Makes Cartridge demagnetisers
Makes an high quality arm load meter.
Sell turntable accessories, calibration, belts etc..
A fascinating, highly accurate and expensive turntable speed tester.
Van Den Hul
Makes a variety of turntable, tonearm and pickup calibration accessories.
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